广西石灰岩山地封山育林效果的分析

ANALYSIS OF THE EFFECT ON PRESERVING HILLSIDES FOR REAFFORESTATION IN GUANGXI KARST REGION

摘要:

根据13个标准地(面积约1600平方米)分析得出:1.石山封山育林10年,可形成由阳性先锋树种组成的次生林;20年,已消失的原石山杂木林常见的组成树种可以重新出现;2.石山封山育林20多年,土壤有机质、全氮和代换量分别由4.148%、0.185%、19.63m·e/100g土提高为8.374%、0.519%、25.61m·e/100g土;3.封山育林10³0年,石山上,亩年平均生长量0.162立方米,产值17.82元(按200元/m³计);第四纪红土台地上,亩年平均生长量0.391立方米,产值43.05元;4.一个地区,已初具规模的封山育林面积覆盖率达到50%以上,其中成林面积覆盖率占23%以上,对于农业的连年稳产可以起到一定的作用。
结论:封山育林是石山地区绿化的主要的战略措施。

Abstract:

According to the analysis on 13 standard samples(area is about 1600m~2), we get the results:1) After 10 years' setting aside hillsides for reafforetation,the rocky hill can form the secondary forest consisting of light demanding pioneer species.After 20 years the typical original species of hybird woodland can reappear on such rocky hills.2) The content of organic matter,total nitrogen and exchange capacity in the soil increase from 4.148 percent,0.185 percent and 19.63m·e/100g soil to 8.374 percent,0.519 percent and 25·61m·e/100g respectively after closing hillsides for reafforestation for more than twenty years.3) After 10——30 year preservation of hillsides for reafforestation,the average per-mu growth volume on rocky hill is 0.162m³,the output value is 17.82 yuan(account according to 200 yuan/m³).On the red earth platform of Quaternary period,average permu growth volume is 0.39m³,output value is 43.05 yuan.4) In one district if the area for reafforestation has attained over 50 percent and the coverage of forest takes over 23 perceet,it can play the role of stabilizing grain yield.Conclusion:The preservation of hillsides for reafforestation is an important strategic measure for revegetating karst region.